Let. I. of Plants, 259 
the fire, before it comes to have thick fumes, it boylsup with a very 
great foame or froath 5 and is the only Gus or Rofin (of the Eleven) 
that hath this property. So that Ifufped; there is'a great quantity of 
fome kind of volatile Spirit, which then flies away; and fo, in break- 
ing through the Oyly parts, huffsthem up to fo great a froath. 
Olibanum yields half a Drachm of Caput Mortuum. | But it is to be 
noted, That the weight is encreafed by certain little Spar-Stones,which 
in the burning of feveral parcels, I always found mixed with this Guns. 
Thefe being picked clean’ out, the Cap. Mort. weigheth not much more 
than that of Maftick. And is in like manner infipid, when the fiid 
Stones are picked out. 
From hence it appears, how proper thefe Gums are for the Con- E 
cottion of Salt Rheums 5 according to what I.have formerly függefted Difconr/é 
from another Experiment. Of Mixturé 
It may alfo be noted, that Rofin and Maflick,, feem to be: more Cap. Ult, 
purely Aeidoleous Gums 5 not only.from their conliftence which is uni- 
form; and their Sell, which is lef {trong and more pleafant : but 
alfo from the Acid Liquor they yield by. Diftillation 5 and in that the 
young Leavs of Fir, and efpecially of Pine, are fowerz and tis pros 
bable that thofe of Maftick are fo likewife. Whereby thefe, and 
other like Gums are more efpecially fitted for the abovelaid purpofe. 
But Olibanum feems, befides its Acidity, to contein fome Volatile Alkaly, 
and fo to be an Acid-Alkaline Gum. For as it hatha ftronger Smell 
than the former, foa hotter Tafte5 both the ordinary effects of an 
Alkaline Sulphur. And being infufed in feveral Menfruums, appears 
h 
Ja to_conftift of two Bodies, one of them more Refímozsthan the other. + 
oar Of which, it is probable, that the one is made by the Acid parts as the 
at other by the Alkaline, Whereby it is very well adapted in fome Cafes, 
pe asina Pleurefie, for removing the Coagulations of the Blood, or its 
ind, difpofition thereunto, 
be! Aja fetida yileds no lef than half its weight or an Ounce of Caput 
ne Mort. that is 8 times asmuch as that of the other Gums, and 48 times 
7 as much as that of fome of them. Yet doth it not contein one grain of 
i Salt, fo far as can be judged by its Taft. Yet the Strength and Loath- 
fa Jomnejs of the smell and Taft of the Gumm do argue it to be highly im- 
pregnated with fome kind of Volatile Alkaly proper to arrelt thofe 
x oftenfive Vapours (toufe the vulgar word‘) which flying, either by 
= = Blood or Nerves, from part to part, do often prove fo trouble- 
me. 
> Gum Arabick yields one Scruple of Cap. Mort. whereof, by the 
Kn Tafte, about 34 part is Salt. 
w Euphorbium yields one Drackm of Caput Mort. of which, by the 
191 ftrength of the Ta/?e, two Scruples feem to be Salt. Which confirms 
a former conjecture (a) of its being an Alkaline Gumur. (2) Of the 
Myrrh alfo yields a Drachm of Cap. Mort, and at lealt two Scruples Luiation 
of Salt. Of the Eleven, thefe two Gums have the greatelt quantity of Bodies, 
ofa fixed Alkaly. Chet. 
Opium yields half a Drachm of Cap. Mort. whereof the one half 
is Salt. 
Aloe yields a Drachm of Cap, wort, conteining about one Scruple of 
Salt, 
Qq2 Scammong 
